At present, in the aviation industry, in order to obtain better control over the costs of developing and manufacturing engines, a “basic” engine is designed from which families and versions of specific engines are derived. Similarly, the manufacturers of controllers have defined a single type of controller per basic engine, which controller is capable of functioning with the engine families and versions derived therefrom.
As a result, the controller must be parameterized as a function of the family and the version of any particular engine under consideration. For this purpose, an identification connector is used which is secured to the engine and which is connected to the controller. The identification connector contains information (in binary-encoded form) relating to the engine characteristics that are to be used by the controller.
FIG. 8 shows an example of an identification connector of the kind to which the present invention applies. The identification connector 100 has a plurality of pins 101 which are connected to one another inside the connector by means of an electric circuit (not shown) that is optionally reprogrammable.
When the electric circuit is not reprogrammable, it is made up of discrete components such as fusible tracks interconnecting the pins of the connector. In conventional manner, information is encoded in the connector by causing some of the fusible tracks to melt. Thus, each pin of the connector corresponds to a binary digit (0 or 1). Once the connector is installed on the engine (i.e. connected to the controller), the controller interprets in binary the electrical connections defined inside the connector in order to acquire the characteristics of the engine.
When the electric circuit is reprogrammable, the binary data may be determined by a switch, for example.
The reliability of the information contained in the identification connector is of major importance, particularly since these connectors have identical keying systems so as to enable them to be installed on all of the controllers. It is the identification connector that serves to authorize or inhibit certain operating characteristics specific to each engine family and version. For example, an engine version or family defined for maximum thrust of 20,000 pounds might be associated with a connector that authorizes thrust up to 22,000 pounds or one that limits thrust to 18,000 pounds. Given that certain components of the engine are not adapted to delivering thrust above 20,000 pounds, or that limiting thrust to 18,000 pounds might prevent takeoff, it can be seen that providing the wrong connector can have severe consequences.
Prior to fitting the engine under the wing of an airplane, the operation of reading the identification connector serves to ensure that the engine has the right characteristics. Thus, it is possible to monitor the decisions that have been made on the basis of the egine control book and avoid fitting a wrong engine which would unacceptable given the downtime and cost that that represents.
At present, there are two ways of reading information contained in an identification connector. The first consists in reading the raw data (i.e. binary data) present in the connector manually. This operation is performed by an operator using an ohmmeter to measure the resistance of each contact of the connector. Once all of the data has been measured, the operator decodes the information using documents from the manufacturer in order to verify that the information encoded in the identification connector matches the characteristics of the engine with which it is associated. This first way of reading is a manual operation that is lengthy and implies a risk of error and of damage while measurements are being taken by the operator, in particular because the contacts within the connector are close together.
The second presently-known way of validating the data contained in an identification connector consists in installing the engine together with the controller fitted with the identification connector under the wing of an airplane in order to read the information encoded in the connector via the on-board computer. This solution is even more time-consuming than the first technique mentioned above. Installing an engine on an airplane and removing it leads to costs in terms of time and labor that are not acceptable in this type of industry.